The various accesses needed through paved roadways to reach utilities and to provide drainage are covered to prevent accidents with a heavy top fitting into a receiving frame imbeeded in the pavement. Often because of its weight the heavy top is just lowered into place and not secured. However, some tops have been fastened in place. For example Mr. Wirz in 1943 in his U.S. Pat. No. 2,323,886 illustrates a manhole cover interlocked with a complementary receiving frame which are so desgined together from the outset. Mr. Blakeman in 1944 in his U.S. Pat. No. 2,363,567 discloses a coverplate with radially operating mechanisms to lock the coverplate with a complementary receiving frame which are so designed together from the outset. Also Mr. Thompson in 1905 in his U.S. Pat. No. 791,381, describes and illustrates his receiver or catch basin having a grate with special receiving structures designed as extensions, which serve as places for securing pivotal hooks mounted on the interior walls of the catch basin at the time of manufacture of the entire covered receiver or catch basin.
Although these prior securement arrangements are provided, there has been a continued production of the standard heavy catch basin grates which are lowered into the receiving frames and not thereafter locked in any way. Yet in some municipal areas there is a need to lock them in place to avoid their loss through theft and vandalism. Therefore there is a need for a locking assembly to be easily installed on existing catch basin grates so they may be locked to their receiving frames to avoid their loss by the acts of thieves and vandals.